. Medical diagnosis for the student and practitioner. fthe percentage of hemoglobin from the appearance of the ordinary stained oreven the unstained smear preparation as may be readily appreciated by referringto Fig. 36, but for accurate work several forms of apparatus have been devised, alldepending upon a comparison of a given specimen of blood, either whole or in aknown degree of dilution, with a fixed color scale. Tallqvists Hemoglobinometer.—77ws, the simplest and least reliable,inaccurate. consists of lithographed color bands. Each has a central perforation andrepresents the color of blo


. Medical diagnosis for the student and practitioner. fthe percentage of hemoglobin from the appearance of the ordinary stained oreven the unstained smear preparation as may be readily appreciated by referringto Fig. 36, but for accurate work several forms of apparatus have been devised, alldepending upon a comparison of a given specimen of blood, either whole or in aknown degree of dilution, with a fixed color scale. Tallqvists Hemoglobinometer.—77ws, the simplest and least reliable,inaccurate. consists of lithographed color bands. Each has a central perforation andrepresents the color of blood in dilutions running from 10 percent, to normal.*A drop of the patients blood is taken up by the absorbent paper andthe resulting stain is placed under the central perforation of the color bandsand comparison is made as soon as the stain has lost its wet gloss, not after,complete drying. * The color scale is bound with 50 sheets of special paper, each divisible into three parts,furnishing material for 150 tests. THE EXAMINATION OF THE BLOOD 117. This is a simple, rapid, but inaccurate method, permitting an error ofat least 10 per cent., and the color scale fades, if not kept from the is distinctly inferior to Dares instrument which takes hardly a minutemore of time. Dares Hemoglobinometer.—A circular disc of tinted glass, representingvariations in blood-coloring matter of a known degree, is brought into directcontrast by transmitted candle light with a film of the fresh whole blooddrawn by capillary attraction between two glass plates, one transparent, the other translucent and detachable observation tube anda circular shield protect the eyesfrom extraneous light, and the per-centage of hemoglobin may be readdirectly from the scale. This ex-cellent instrument may be used indaylight if pointed at some darkobject, and its readings are notmaterially affected by an excess ofleucocytes.* Von Fleischls Hemoglobino-meter.—This well-known instrumentor its more


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Keywords: ., bookcentury1900, bookdecade1920, booksubjectdiagnos, bookyear1922